def main():
    x = int(input())

    print('Yes' if x >= 30 else 'No')


if __name__ == '__main__':
    main() def main():
    x = int(input())

    print('Yes' if x >= 30 else 'No') main x = int(input()) x int(input()) int input() input print('Yes' if x >= 30 else 'No') print 'Yes' if x >= 30 else 'No' x >= 30 x 30 'Yes' 'No' if __name__ == '__main__':
    main() __name__ == '__main__' __name__ '__main__' main() main def main():
    x = int(input())

    print('Yes' if x >= 30 else 'No') def main():
    x = int(input())

    print('Yes' if x >= 30 else 'No') main
def main():
    x = int(input())

    print('Yes' if x >= 30 else 'No')


if __name__ == '__main__':
    main()
